In the literature, bad breath is usually referred to as halitosis or oral odor. The term halitosis comes from the Latin Halitus, meaning breath and the Greek -osis, meaning abnormal condition. On one hand most people are not aware of their own breath (whether sweet or bad), while on the other hand most people usually feel too uncomfortable to inform a person that they have bad breath.
The breath freshening and oral hygiene areas are large markets which are continuing to grow. For example, market research has shown that consumers in the USA spent US$1.8 billion on toothpaste in 2000, around US$715 million on oral care gums, almost US$740 million on mouthwash and other dental rinses, and almost US$950 million on toothbrushes and dental floss. Although many of those products are primarily for the maintenance of oral health, consumers also buy them to ensure that their breath is pleasant. The US$625 million spent on breath fresheners other than gums and mouthwash, for example breath mints, is directly for this purpose.
The mouth and nasal passages are home to hundreds of bacterial species with various nutritional preferences. In otherwise healthy people, the very back of the tongue, rather than the teeth and gums, is the main source of bad breath. This region is poorly cleansed by saliva and contains numerous tiny invaginations in which bacteria can hide. These bacteria putrefy postnasal drip and other oral debris that can collect there. These tiny organisms thrive on proteins, and the chemical compounds that result from the digestion of these proteins include some fetid compounds. At any given time, oral bacteria may be producing hydrogen sulfide (rotten egg smell), methyl mercaptan and skatole (also present in feces); indole; cadaverine (associated with rotting corpses); putrescine (found in decaying meat); and isovaleric acid (the smell of sweaty feet).
Additional oral sources of bad breath include poor oral hygiene (especially if proteinaceous particles are left between teeth), gum inflammation, faulty dental work, unclean dentures and abscesses. Because a steady flow of saliva washes away bacteria and its resultant odorous chemical products, anything that promotes dryness (for example, breathing through one's mouth, fasting, prolonged talking, stress and many medications) can exacerbate the situation.
Some bad breath seems to be associated with actual periodontal disease and is therefore a useful clue to physicians and dentists. The presence of several key bacteria such as Treponema Denticola, Porphyromonas Gingivalis and Bacterioides Forsythesis can be founding plaque or the tongue.
The chemical composition and concentrations of the odorous compounds associated with bad breath have been studied and reported in the literature (Krotoszynski et al, 1977; Tonzetich, 1971). The most common odorous compound in levels above the human detection threshold is hydrogen sulfide (>250 ppb), followed by other sulfur containing compounds such as methyl mercaptan and dimethylsulfide. The human nose can detect hydrogen sulfide levels as low as 0.02 ppm (v/v), and levels of 0.025 ppm and greater are deemed to be characteristic of bad breath in a person.
While there are numerous products and technologies that cure or treat bad breath, there are surprisingly few devices available on the market to help identify and alert a user to bad breath.
One clinical instrument which is currently used to measure ppm levels in patients' breath is the Halimeter™ breath tester (available from Interscan Corporation, Chatsworth, Calif.), which costs US$1200 and is not portable. Another device is the BreathAlert™ breath tester (available from Tanita Corporation, Arlington Heights, Ill.). This is a small hand-held unit which costs about US$25. It uses a heated wire to detect sulfide compounds in a person's breath and gives a read-out in four levels.
The Halimeter™ breath tester has high sensitivity for hydrogen sulfide but low sensitivity for methyl mercaptan, which is a significant contributor to halitosis caused by periodontal disease. The BreathAlert™ breath tester unit was sensitive to sulfide concentration, but gave different numbers depending on the position of the meter from the mouth and how the user breathed or blew into the unit's intake area.
There are also other devices which use oral bacteria measurements to indicate bad breath (for example, a device available from Soft Lines International), but these are very expensive and take time to provide an indication of bad breath, and are therefore not particularly useful to a user who wants to conduct a “spot check” on their breath.
It would be very useful if users were able to check their breath before meetings or dates, while at the office or after a meal.
There is therefore a clear need for an affordable, portable and rapid indicator for testing for bad breath.